CASE REPORT Projected Complex Sensations After Interscalene Brachial Plexus Block Mattias Casutt, MD, Georgios Ekatodramis, MD, Konrad Maurer, MD, and Alain Borgeat, MD Department of Anesthesiology, Orthopedic University Clinic Zurich/Balgrist, Zurich, Switzerland P hantom pain is described as a strong mispercep- tion, the incidence of which is approximately 50%, of the presence of a limb after it has been amputated (1). This has to be differentiated from so- called phantom sensations—a misinterpretation of the mass, length, movement, and position in space of the deafferentated limb, which occurs in nearly 75% of patients after amputation (2). Pain from phantom sen- sations of a blocked part of the body has been reported after subarachnoid anesthesia (3) and IV regional an- esthesia (4). Bromage and Melzack (5) described phan- tom sensations in 86% of patients after brachial plexus anesthesia. We report a case with complex sensations mimicking phantom sensations after an interscalene block (ISB). Case Report A 62-yr-old, ASA status II woman was admitted for right total shoulder replacement. The patient was otherwise healthy; she had no cardiac, esophageal, or visceral disease. The left shoulder was successfully operated on 1 yr earlier in our institution under ISB with catheter and general anesthe- sia with propofol target-controlled infusion technique (TCI). The anesthesia procedure had been uneventful. The patient was very satisfied with the postoperative analgesia manage- ment and therefore asked for the same type of anesthesia as the year before. She was premedicated with midazolam 7.5 mg orally 1 h before anesthesia. Before the ISB was performed, the patient was supine, her head was slightly turned on the opposite side, and her elbow was flexed with her right hand lying on her left chest. The interscalene brachial plexus was identified by using a nerve stimulator (Stimuplex-HNS II; B. Braun Melsungen AG, Melsungen, Germany) connected to the proximal end of the metal inner needle (Stimuplex A; B. Braun Melsungen AG). Contraction of the triceps was elicited on the first attempt with a thresh- old stimulation of 0.3 mA and an impulse duration of 0.1 ms. A catheter (Polymedic, 22-gauge with stylet; Te me na, Bondy, France) was introduced distally between the anterior and middle scalene muscles for 3 cm without producing dysesthesia or pain according to the “cannula over needle” technique. Then, the catheter was subcutaneously tunneled over 4 cm through an 18-gauge IV cannula and fixed to the skin with adhesive tape (Tegaderm; 3M Health Care, Borken, Germany). The ISB was performed with 20 mL of 0.75% ropivacaine and 20 mL of 0.5% ropivacaine and ad- ministered through the catheter, with the hand lying on the lower part of the left hemithorax. Within 20 min, the patient had a complete sensory block (inability to recognize cold temperature) and motor block (inability to extend the arm). General anesthesia was performed with TCI propofol (TCI pump, Graseby 3500; SIMS Graseby Limited, Watford, Herts, UK). Tracheal intubation was facilitated with rocuro- nium, and 0.1 mg of fentanyl was given before intubation. Surgery was uneventful and lasted 180 min. Upon arrival in the recovery room, the patient was fully awake and imme- diately complained about a constant, strong, and burning pressure pain in her right hand over the sternum; the pain was not modified by respiration. The pain intensity was 80 on a visual analog scale (VAS) from 0 to 100 (0, no pain; 100, worst pain imaginable). She explained she felt the pain located in her right hand on her chest (the last position of her arm before the ISB was done), although her hand was on her right side, slightly elevated, within the abductor splint. However, the shoulder was completely pain free (0 on the VAS), and the patient could not feel her arm and forearm. Electrocardiogram, creatine kinase, CK-MB, and troponin, which were all within normal range, were done to exclude cardiac ischemia. The patient received propacetamol 2 g IV and morphine 7.5 mg subcutaneously; these slightly re- duced the pain on the thorax from 80 to 50 on the VAS. Six hours after the initial ISB, a continuous infusion of ropiva- caine 0.2% for the next 72 h was started by using patient- controlled interscalene analgesia at a rate of 5 mL/h plus a bolus of 4 mL with a lockout time of 20 min. The VAS over the sternum (in her right hand, as reported by the patient) remained stable, at approximately 40, during the continuous infusion of ropivacaine for the next 72 h, although the shoul- der and whole right upper limb were completely pain free. Rehabilitation was started as usual on the second day after surgery (VAS, 0). On the third postoperative day (72 h after the ISB), the interscalene catheter was removed. After the infusion of ropivacaine was stopped, pain on the thorax steadily decreased until it disappeared (VAS, 0) 2 h later. At this time, the patient also had no pain in the shoulder. After the analgesic action of ropivacaine had completely disap- peared, there was no sign of brachial plexus or vagal nerve irritation. Accepted for publication December 18, 2001. Address correspondence and reprint requests to Alain Borgeat, MD, Chief of Staff, Anesthesiology, Orthopedic University Clinic of Zurich/Balgrist, Forchstrasse 340, CH-8008 Zurich, Switzerland. Address e-mail to aborgeat@balgrist.unizh.ch. ©2002 by the International Anesthesia Research Society 1270 Anesth Analg 2002;94:1270–1 0003-2999/02